Lifting jack



May 20, 1930.

L. C. STUKENBORG LIFTING JACK Filed July 8, 1927 INVENTOR Zauzls CSill/(61111049 ATTORNEY Patented May 20, 1930 UNITED STATES.

PATENT OFFICE LOUIS .C. s'ruxmono, OF MEMPHIS, TENNESSEE, ASSIGNOR TOOILDBAULIO LET COMPANY, OF MEMPHIS, TENNESSEE, A CORPORATION OF DELAWAREL'm'rme JACK Application filed July 8,

My invention relates to lifting jacks and more particularly to ahydraulic or fluid pressure Jack.

An object of the invention is to provide a lifting jack which requiresbut a minimum of pressure to lift and support a maximum load.

Further the invention provides a hydraulic jack wherein fluid isnormally contained in an elevating piston which is conducted therefromand discharged under pressure beneath the piston to elevate the latter,the fluid being conducted back into the hollow piston by the pressurethereof against the fluid head as the piston descends to normalposition.

The invention also contemplates a lifting head designed to lift andsupport wheeled vehicles.

Still another object resides in the provi- .sion of a hydraulic or fluidpressure jack having means for automatically stopping the ascent of thepiston when the latter reaches a predetermined point, thus obviating thedanger of the piston moving from its cyllnder.

With the preceding and other objects and advantages in mind, myinvention consists in the combination, construction and arrangement ofparts and objects to be hereinafter specifically referred to, claimedand illustrated in the accompanying drawing, wherein,

Figure 1 is a fragmentary top plan view of a hydraulic jack constructedin accordance with my invention, and

Figure 2 is a vertical sectional vlew of the same.

Referring to the invention a vertical cylinder 5 is provided having aremovable bottom cap 6 and equipped with a stufling box? at 1ts upperends. Reciprocable in the cylinder 5 is a hollow piston 8 having a lowerclosed wall 9 and which is slidable through the smiling box, and aackinggland 10 secured to the up er end 0 the stufling box.

X lifting head is provided for ralslng and supporting motor vehicles andcampuses a central rectangular body 11 having a central opening 12 inits under face into which the upper end of the hollow piston projects sothat e body 11 rests directly upon the upper end of the piston.- Toreceive and support vehicle 1927. Serial No. 204,327.

wheels, channeled shaped tracks orguides 13 upon which an automobile isdriven, is provided at opposite sides of the body 11.

In order to support and rigidly brace the track or guides 13 a pair ofsubstantially longitudinal bowed I beams is provided. These I beams haveintermediate parallel portions 15 embracing the opposite ends of thebody 11 and secured thereto by fastenings 16. AS illustrated in Figure 2the extremities of the I beams 14 extend laterally beneath thechannelled shaped tracks or guides and are electrowelded or otherwisesecured thereto adjacent their ends.

Extending vertically through the hollow piston is a fluid conductingpipe 17 having its lower end threaded in an opening 18 in the closed end9 of the piston to discharge fluid into the cylinder 5. A fluid returnpipe 19 also extends vertically through the hollow piston and has alateral branch 20 at its upper end extending transversely across avertical opening 21 in the body 11 and communicating with the inlet of arotary pump 22 driven by an electric motor 24, the pump motor beingsupported upon a shelf 25 extending from one of the I beams 14 to theadjacent track 13, and a control switch 26 in circuit with the motor isattached to this track. The supply pipe 17 also has a lateral branchpipe 27 at its upper end extending across the opening 23 andcommunicates with a check valve 28, the latter in turn havingcommunication with the pump outlet.

To control the passage of fluid to either the P y P p 1 valve 28, andleading therefrom is an outlet pipe 30 which, when the valve is inclosed position, directs the fluid into the hollow piston. a

An actuating arm 31 is provided with a cylinder or hollow piston 8,athree way valve, 29 is interposed in the branch 27 to the supbetweenthe latter and the check three way valve, and connected therewith is alongitudinally movablehorizontal actuating lever 32 having one endsupported in a bracket or guide 33-upon the under face of one of thetracks 13 ad acent the switch 26.

at a predetermined height a vertical branch In order to stop the ascentof the piston of the piston as it into the piston by way pipe 34 havingcommunication with the pipe With the piston in its extreme lowerposition as illustrated in Figure 2, the pump being in operation, thevalve 29 is opened by manipulation of the handle 4. Vacuum in the pipe19 reduced by the pump 22 lifts the liquid from the hollow pistondirecting it under compression into the cylinder 5 by way of thedischarge pipe 17 causing ascent the cylinder gradually fills. By reasonof the inlet in the branch pipe 34 being above the inner end of the pipe19, the pump will cease to function as above stated when the liquid inthe hollow cylinder re cedes to a predetermined point, the piston beingsupported in elevated position to retain its head in elevated positionby the column of liquid in the cylinder. .To cause the piston to descendthe valve 29 is actuated to sever communication between the pump andsupply pipe 17 and establish communication between the bleed pipe anddischarge pipe.

The bleed pipe belng open pressure is re-.

lieved from the piston allowing it to gravitate forcing the liquid fromthe cylinder through the discharge pi e and emptying oi the bleed pipe.What is claimed is 1. In a vehicle lifting device of the classdescribed, a stationary cylinder, a piston slidable in' the cylinder, abody rigidly mounted on the upper end of the piston,

means mounted on sald body .and constructed for accommodating andsupportinga vehicle,

a motor driven pump on said vehicle supporting means, and valved pipingconnected with the pump and associated with the piston, said valvedpiping including a. discharge pipe connected through a valve with thepump, a return pipe extending from the valve, the valve being movable toposition for affording communication between the discharge pipe and thepump or another position affording communication between the dischargepipe and the return-pipe and a supply pipe connected with the pump.

2. In a vehicle lifting device of the class described, a stationarycylinder closed at its bottom, and providedat its top with a stuflingbox, a hollow piston slidable in said cylinder, said piston being closedat its bottom, and open at its top, a body having a socket in its undersidereceiving and closing the upper end of said piston, vehiclesupporting means carried by the body, a motor driven pump carried bysaid vehicle supporting means, and piping connected. with the pump andextending into saidpiston, said piping including a valve to aflordcommunication between the cylinder and pump'or the piston and pump.

3. In a structure of the class described, a cylinder, a stuffing box atthe upper end of the cylinder, cylinder and through said stuffing box, ahead supported on the upper end of the piston, a fluid circulating pumpon said head, a valved conducting pipe leading from the pump on one sideand down through the hollow piston, and communicating at its bottom withsaid'cylinder for delivering fluid into the cylinder to elevate thepiston, a return pipe connected with the other side of the pump andextending down into the piston, and terminating in spaced relation tothe bottom of said piston, and a branch pipe communicating withthepiston and the valved conducting pipe, the lower end of said branchpipe terminating above the lower end of said conducting pipe for causingthe pump to cease functioning when the liquid in the piston reaches apredetermined point.

4. In a jack structure, a cylinder, a hollowpiston therein forming areservoir, a pump, a discharge pipe between the cylinder and one side ofthe pump, a valve in said plpe, a return pipe connected with the valveand adapted to discharge into the piston and a supply pipe between a lowpoint in the piston and the other side of said pump.

' LOUIS G. STUKENBORG.

